Many people are affected by urinary incontinence. Incontinence is particularly common in the elderly, urinary incontinence is present in approximately fifty percent of nursing home patients, and urinary incontinence is a well known urologic problem in women. It will affect nearly all women in some form during their lifetime, and it is of significant medical and social concern to all humans who experience it. Urinary incontinence arises from the anatomy and from the physiology of the urinary tract, which is composed of a bladder and a sphincter. Anatomically, the bladder consists of the bladder musculature, also known as detrusor, and the trigone. The sphincter includes the bladder neck and the proximal urethra. The detrusor muscle is innervated by the pelvic nerve through the parasympathetic nervous system, and the bladder neck and proximal urethra are innervated by the sympathetic nervous system.
The major functions of the bladder are the storage and expulsion of urine. The bladder is responsible for accommodating increasing volumes of urine at low pressures. Normally, the bladder remains closed during bladder filling and continence is maintained as long as the bladder neck and urethral pressure exceeds intravesical pressure. Voluntary voiding occurs when intravesical pressure exceeds bladder neck and urethral pressure, and involuntary voiding also known as involuntary incontinence occurs when the travesical pressure exceeds the bladder neck and urethral pressure. Involuntary incontinence also known as urge incontinence and overactive bladder, occurs with a loss of a large volume of urine accompanied by symptoms of urgency, frequency and nocturia caused by an unstable bladder or detrusor instability. The patient may lose urine with a change in position or with auditory stimulation. The loss of small volumes of urine usually occurs because bladder over distension by a large amount of residual urine referred to as overflow incontinence. Urinary incontinence is also known as overactive bladder with symptoms of urinary frequency or urge incontinence.
The present management of incontinence consists in administering a smooth muscle relaxant, such as oxybutynin, which acts directly on the smooth muscle at the site distal to the cholinergic receptor. The prior art administered oxybutynin alone for this stated therapeutic purpose. The prior art usual dose for the pharmacologic management of incontinence is repeated, nonsustained and noncontrolled doses from two-to-four times a day for oxybutynin. The prior art administered separately the steriods, estrogen and/or progesterone hormone replacement therapy however, this steroid therapy is insufficient for the management of incontinence.
In light of the above presentation it will be appreciated by those versed in the medical and pharmaceutical dispensing arts to which this invention pertains that a pressing need exists for a therapeutic method that can deliver the therapeutic drug oxybutynin in a controlled, sustained-extended dose to a patient in clinical need of incontinence management. The pressing need exists for an oral method of therapy that can deliver oxybutynin alone at a substantially sustained release constant dose per unit time for its therapeutic effect. The need exists additionally for a method for delivering a dose of oxybutynin once-a-day, when indicated, for its intended therapy while avoiding an overdose and for lessening the side effects that can accompany the drug. The pressing need exists further for a method that can administer oxybutynin in combination with another and different drug, or in different therapeutic programs for the management of incontinence and for the management of health and disease.
It will be appreciated by those skilled in the medical and pharmaceutical arts to which this invention pertains, that if a novel and unique method of administration is made available that delivers oxybutynin alone, or in combination with another drug in a therapeutically effective dose over a sustained time for the management of incontinence, while lessening the incidence of over and under dose, such a method of therapy would represent an advancement and a valuable contribution for providing practical therapy.